Electric-arc lamp.



PATENTED SEPT. 8, 1903.

C. E. FOSTER.

ELECTRIC ARC LAMP.

APPLICATION FILED JULY 5, 1902.

K0 MODEL.

In: nonms FUKRS on, PnoToLmaQ, wumusrom u. c.

UNITED STATES Patented September 8, I903.

PATENT ()EEIcE.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 738,426, dated September 8 1903.

7 Application filed July 5, 1902.

To all whom it may concern.-

Be it known that 1, CHARLES EDWIN Fos- TER, a subject of the King of Great Britain and Ireland, residing at 34 Corsehill street, Mitcham Lane, Streatham, S. W., (late of 24 Keymer road, Streatham Hill,) in the county of Surrey, England, have invented a new and useful Improved Method of Actuating the Carbon-Feeding Mechanism of Electric-Arc Lamps of the Open and Inclosed Types, of

which the following is a specification.

This invention relates to improved means for actuating and controlling the carbon-feeding mechanism of electric-arc lamps by the expansion and contraction of a suitable wire, ribbon, strip, or rod or combinations of separate Wires, ribbons, strips, or rods of metal or other suitable substance through which the current or a portion thereof passes while the lamp is at work.

In all arrangements (so far as I am aware) hitherto proposed in which a single expansivestrip has been bent around pulleys or otherwise so arranged as to involve a change in form the action due to the expansion and contraction is so sluggish as to render the lamps commercially unsuccessful.

This invention consists in the novel construction and combination of the parts hereinafter fully described and claimed.

In my invention the ratio of multiplication of the movements due to the expansion and contraction is large and friction is reduced to a minimum, whereby the lamp is rendered sensitive and rapid in action, while at the same time itis of simple and cheap construction. As the total longitudinal expansion of the hot wire is small as compared with the motion it is desired to give to the carbon in order to establish the arc, the multiplication of that motion must be correspondingly large.

I will now describe my invention with reference to the accompanying drawings, which illustrate two examples thereof and in which Figures 1 and 2 are elevations, partly in section, of an arc-lamp comprising my invention, showing the upper carbon in different positions. Fig. 3 isa view, partlyin section, of a modification, showing only the parts comprising my invention.

The same reference-letters indicate the Serial No. 114,385. (N0. model.)

same parts in the several figures of the drawings.

a a a represents thelamp-frame; b, a cross bar or casting fixed to the lamp-frame.

c is a rod or strut of metal or other suitable material, (hereinafter called the multiplying-rod,) one end of which is pivoted at o in casting b, said end being pointed or formed as a knife-edge and bearing in a corresponding recess in casting b, as shown, so that it can swing with a minimum of friction in the approximately horizontal directions, (indicated by the arrows X and Y.)

01 is the expansive wire or strip, which is preferably as fine or thin as it is possible to use for the purpose, said wire or the like being connected (in any convenient manner) at one end of the regulating-screw e, held by but insulated from casting b. The other end of the wire or strip (1 is connected to the multiplying-rod o by means of the screwfor in any other convenient manner.

g is a spring connected (by any suitable means) at one end to casting b. The other end of springfis connected to the multiplying-rod c by the eye it or otherwise, so that the force of the tension in said spring may act upon the multiplying-rod so as to move or tendto'move it in the direction of the arrow X, and thus putthe wire or strip (1 under tension. The tension on wire 01 when no current is passing and the lamp mechanism is at rest is such that the resultant force (indicated by arrow Y) will be equal but opposite to the resultant spring force, (indicated by arrow X,) or, in other words, the tension on wire or strip 61 is such that it will retain the parts in the position shown in Fig. 1, with the carbons in contact.

The lover or connection j, through which movement is communicated to the carbonclutch, is pivotally connected to a link j, which latter is pivotall y connected to the multiplying-rod c, as shown at k. The carbonclutch (marked Z) is of the well-known tilting type; but any other known or convenient form of clutch may be employed.

In the modification shown in Fig. 3 a rocking bar orlink m is pivoted or otherwise mounted on the regulating-screw e, and two separate expansive wires or strips (marked d d) are connected, as shown, to said rocking bar or link m, the lower end of wire d being connected to a pin or hook a, mounted on, but insulated from the lower casting 0 of the lamp. Thenumberofseparatestraightwires or strips 01 d and the number of rocking links, such as m, may be varied, as desired, as also the number of regulating-screws e.

In lieu of the spring 9 I may employ a balance-weight and lever or levers for exerting a force on the multiplying-rod c in the direction of the arrow X or opposite to the direction of the retaining force exercised by wire or strip d.

One of the circuit-wires is connected (by connection marked 9, Figs. 1 and 2) to the regulating-screw c,as shown, or otherwise connected so that the current (or a portion thereof) passing through the upper carbon will also pass through or along the expansive wire (or wires) d when the circuitis closed. The other circuit-wire may be connected (by connection marked (1, Figs. 1 and 2) to the lower-carbon holder or carbon through the lower lampframe a a which is insulated from casting 0 and from the upper part of the frame. The circuit connections may be made in any other convenient manner.

The working of my invention is as follows: Assuming that no current is passing,the mechanism of the lamp will be at rest in the position shown in Fig. 1, the upper and lower carbons being in contact. Now when the electric circuit is closed the whole or a portion of the current passing through the lamp passes through or along the wire d, which is thus caused. to expand longitudinally, and so relieve the tension upon itself. This allows the spring g (or the balance-weight, as the case may be,) to act on the multiplying-rod 0, so as to move the end of said rod in the direction of the arrow X, so that the rod 0 multiplies and transmits the motion (due to the expansion of wire or strip d) through the link or connection j and leverj to the carbonclutch, which is thus actuated so as to lift the upper carbon and strike the arc. When the arc is struck and the lamp is burning, any increase in the current will cause a further expansion of the wire d, and so will allow the spring g to further lift the upper carbon, thus increasing the length of the arc and bringing the current down until a working balance is arrived at. On the other hand,

any diminution of the current will cause the wire or strip 61 to contract, and so draw the end of the multiplying-rod c in the direction indicated by the arrowY, and thus, through the link or connection j and leverj, causes the upper carbon to drop slightly, which reduces the length of the arc and again increases the current. IVhen the circuit is again broken, the wire at cools and by contract-ing draws the end of the multiplyingrod back, (in the direction of arrow Y,) thereby lowering, through link j and leverj, the upper carbon into contact with the lower carhon-that is to say, the parts are returned to the position shown in Fig. 1.

It will be seen that as the spring 9 has to exercise a force necessary to lift the upper carbon and clutch when the circuit is closed the wire or strip d when the lamp is at work will only have to oppose a small part of the spring force-namely, that part which is not absorbed by the weight of the carbon and clutch. Thus the hot wire is only under a very slight strain.

Variations may be made in the arrangements above described without departing from my invention. For instance the strip d and spring g instead of being connected to casting I) might be connected to the top casting or cover of the lamp.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In an arc-lamp, the combination, with a carbon-holder, of a pivoted rod, lever mechanism connecting the said rod with the carbon-holder, means for moving the said rod automatically in one direction, and an ex pansion-wire for moving the said rod in the other direction, said wire being arranged in the path of the current to the lamp and at an acute angle with the said rod and being secured at one end to the said rod.

2. In an arc-lamp, the combination, with a carbon-holder, of a pivoted rod, lever mechanism connecting the said rod with the carbon-holder, means for moving the said rod automatically in one direction, an expansionwire for moving the said rod in the other direction, said wire being arranged in the path of the current to the lamp and at an acute angle with the said rod and being secured at one end to the said rod, and means for adjusting the tension of the said wire.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES EDWIN FOSTER.

Witnesses:

D. H. LUsoN, WALTER E. ROCHE.

IOC 

